Comparison of cytotoxicity between 3D printable resins and heat-cure PMMA.

Aim: The aim of this study was to evaluate and compare the cytotoxicity of polyurethane and polyoxymethylene printable resins with conventional heat cure polymethyl methacrylate denture base resins. Methods: The study followed ISO-10993-5 guidelines. It comprised of three groups. Fifteen cuboidal samples measuring 10x10 × 10mm dimension were prepared for each group. The polymethylmethacrylate samples were fabricated using conventional denture processing techniques, while the polyoxymethylene samples were printed using fused deposition modeling and the polyurethane samples using stereolithography technique. Post fabrication the samples were evaluated for cytotoxicity using the MTT assay with the VERO cell line. The percentage of cell viability was calculated to determine the cytotoxic effects. Results: Statistical analysis revealed a significant difference in the cell viability of the experimental groups (p ≤ 0.0001). The polyoxymethylene group showed the highest % cell viability (62.78 %), followed by the polymethylmethacrylate group (52.43 %), and the least was observed in the polyurethane-based resin group (46.47 %). The findings indicate polyoxymethylene group displayed least cytotoxicity, followed by polymethylmethacrylate, and polyurethane-based resin. Conclusion: Polyoxymethylene resin exhibited the minimum cytotoxic properties among the tested materials, followed by polymethylmethacrylate and polyurethane resin.

Retention and Patient Satisfaction of Conventional Over Simplified Non-Balanced Maxillary Removable Complete Dentures.

AIM: Insufficient evidence is available in quantifying the retention between simplified and conventional non-balanced dentures. The aim of the study was to quantify and compare the maxillary denture retention and patient satisfaction between conventional and simplified removable non-balanced complete dentures. METHOD: This randomized clinical trial recruited 44 patients (n=22) with definitive criteria. Simplified and conventional non-balanced complete dentures were fabricated for the intervention groups. The denture retention of maxillary complete dentures was assessed with a dynamometer and patient satisfaction with a visual analogue scale. The mean retention of maxillary denture and satisfaction were recorded at 0-,3-, and 6 - month intervals. The data were statistically analyzed. (α=.05). RESULTS: The mean ±SD of retention for conventional denture at 0, 3, and 6 months by dynamometer ranged from 122 ± 1.64 N to 121 ± 1.57 N and 111 ±1.45N to 110±1.97 N for the simplified denture. The mean ±SD of visual analogue score varied between 9.45±0.35 to 7.19± 0.69 for conventional dentures and 8.00 ±1.39 to 6.81±0.82 for simplified dentures. The repeated ANOVA, t-test and post-hoc Bonferroni revealed statistically significant differences between the two types of denture. (P⟨.05) Conclusion: Numerical retention and satisfaction were higher in conventional non-balanced dentures than simplified dentures.

Assessing the Compliance of Dental Clinicians towards Regulatory Infection Control Guidelines Using a Newly Developed Survey Tool: A Pilot Cross-Sectional Study in India.

Adherence to the dental practice regulatory guidelines instituted during the COVID-19 pandemic is essential to minimize the transmission of SARS-CoV-2 strains. Given the lack of a valid and reliable survey tool to assess the adherence to dental practice guidelines, this study aims to develop, validate, and test a survey tool on a pilot sample of dental clinicians practicing in India. A survey tool was developed/validated through a sequential phasic approach: Phase I- developing survey using conceptual and literature framework; Phase II: ascertaining its validity and reliability; Phase III: pilot testing; and Phase IV: assessing construct validity by exploratory factor analysis (EFA) on the responses collected in Spring 2021. The EFA was achieved using a traditional unweighted least squares extraction method through a varimax rotation with Kaiser normalization. A six-factor solution with 18 items (with the global reliability of 86%) related to screening, regular infection prevention measures, infection control inside the dental operatory, disinfection of the dental unit, disposal, and other COVID-19-specific preventive measures were extracted. Our sample had higher compliance with regard to providing alcohol-based hand scrubs, providing protective gear to attendees, collecting travel/medical history, and screening patients for COVID-19 symptoms. In contrast, less compliance was observed regarding the use of paperless forms of practice and rubber dams in the operatory. The use of a validated survey tool ensures the collection of reliable and valid data, which can serve as baseline data to measure the uptake and effectiveness of dental practice regulatory guidelines in a clinical setting and community dental health clinics.

To block, or not to block is it still the question? Effectiveness of alpha- and beta-blockade in phaeochromocytoma surgery: an institutional analysis.

INTRODUCTION: Phaeochromocytomas/paraganglioma (PPGL) surgery was historically associated with significant risks of perioperative complications. The decreased mortality (<3.0%) had been attributed in part to optimal preoperative alpha-blockade. The value of alpha-blockade in decreasing morbidity is being challenged. The aim of our study is to present an institutional experience of preoperative alpha-blocking of PPGL and its effect on cardiovascular stability and postoperative morbidity. METHODS: A retrospective study using data from our institutional database was conducted. All patients undergoing adrenalectomy for PPGL from October 2011 to September 2020 were included. All patients were routinely alpha-blocked. Intraoperative cardiovascular instability (ICI) was assessed through number of systolic blood pressure (SBP) episodes >160mmHg, SBP <90mmHg, the need for vasoactive drugs and volume of intraoperative crystalloids administered. Morbidity was also evaluated. RESULTS: A total of 100 consecutive patients undergoing surgery were identified of whom 53 patients had complete anaesthetic records available for analysis. Thirty-two patients (60%) had at least one episode with an SBP >160mmHg. Nine (17%) cases had no intraoperative hypotensive episodes, while 3 (6%) patients had >10 intraoperative episodes of an SBP <90mmHg. Twenty-one (40%) patients received vasoactive drugs during surgery. The median volume of intraoperative crystalloids was 2 litres (1-4). Postoperatively, no patient experienced cardiovascular complications, including arrhythmia or myocardial ischaemia. Only two were admitted to an intensive care unit (ICU) and one 30-day readmission occurred. CONCLUSIONS: Cardiac instability remained significant in PPGL surgery despite optimal alpha- and beta-blockade. While omitting blockade would appear empirically questionable, a randomised controlled trial (RCT) of surgery with and without alpha-blockade will provide an answer.

To block, or not to block is it still the question? Effectiveness of alpha- and beta-blockade in phaeochromocytoma surgery: an institutional analysis.

INTRODUCTION: Phaeochromocytomas/paraganglioma (PPGL) surgery was historically associated with significant risks of perioperative complications. The decreased mortality (<3.0%) had been attributed in part to optimal preoperative alpha-blockade. The value of alpha-blockade in decreasing morbidity is being challenged. The aim of our study is to present an institutional experience of preoperative alpha-blocking of PPGL and its effect on cardiovascular stability and postoperative morbidity. METHODS: A retrospective study using data from our institutional database was conducted. All patients undergoing adrenalectomy for PPGL from October 2011 to September 2020 were included. All patients were routinely alpha-blocked. Intraoperative cardiovascular instability (ICI) was assessed through number of systolic blood pressure (SBP) episodes >160mmHg, SBP <90mmHg, the need for vasoactive drugs and volume of intraoperative crystalloids administered. Morbidity was also evaluated. RESULTS: A total of 100 consecutive patients undergoing surgery were identified of whom 53 patients had complete anaesthetic records available for analysis. Thirty-two patients (60%) had at least one episode with an SBP >160mmHg. Nine (17%) cases had no intraoperative hypotensive episodes, while 3 (6%) patients had >10 intraoperative episodes of an SBP <90mmHg. Twenty-one (40%) patients received vasoactive drugs during surgery. The median volume of intraoperative crystalloids was 2 litres (1-4). Postoperatively, no patient experienced cardiovascular complications, including arrhythmia or myocardial ischaemia. Only two were admitted to an intensive care unit (ICU) and one 30-day readmission occurred. CONCLUSIONS: Cardiac instability remained significant in PPGL surgery despite optimal alpha- and beta-blockade. While omitting blockade would appear empirically questionable, a randomised controlled trial (RCT) of surgery with and without alpha-blockade will provide an answer.

Dimensional accuracy of vinyl polyether and polyvinyl siloxane impression materials in direct implant impression technique for multiple dental implants.

PURPOSE: The present study compared the dimensional accuracy of vinyl polyether silicone (VPES) and polyvinyl siloxane (PVS) impression materials used for non-splinted (NS) and splinted (S) direct open-tray impression techniques for multiple implants inserted in simulated edentulous mandibles. MATERIALS AND METHODS: A mandibular stainless steel model with eight internal connections for implant analogs was fabricated to simulate a clinical scenario. The acrylic resin splinted and non-splinted direct impressions were obtained for both VPES and PVS materials. Seventy-two cast samples were divided into four groups based on the impression techniques and materials used. The dimensional accuracies of the casts were measured in three different axes using a computerized coordinate measuring machine (CMM), and were statistically compared. RESULTS: The differences in the distortion values between the VPES and PVS impression materials were not statistically significant. Similarly, the differences between the splinted and non-splinted groups among the VPES and PVS materials were not statistically significant. CONCLUSION: The casts fabricated from VPS or PVS impression materials provide similar dimensional accuracy regardless of the implant splinting method.

Splenocystojejunostomy for the treatment of a symptomatic splenic pseudocyst.

Pancreatic pseudocyst is a widely recognised local complication following acute pancreatitis. Typically occurring more than four weeks after acute pancreatitis, a pseudocyst is a mature, encapsulated collection found within the peripancreatic tissues manifesting as abdominal pain, structural compression, gastroparesis, sepsis and organ dysfunction. Therapeutic interventions include endoscopic transpapillary or transmural drainage, percutaneous catheter drainage and open surgery. We present our management of idiopathic chronic pancreatitis complicated by a pancreatic pseudocyst extending to the splenic capsule in a 38-year-old man. A trial of conservative management was sought, but later escalated to percutaneous fluoroscopic drainage. Despite a period of volume reduction of the pseudocyst, reaccumulation occurred. We describe successful surgical treatment via means of a splenocystojejunostomy and subsequent pain reduction.

The PanSurg-PREDICT Study: Endocrine Surgery During the COVID-19 Pandemic.

BACKGROUND: In the midst of the COVID-19 pandemic, patients have continued to present with endocrine (surgical) pathology in an environment depleted of resources. This study investigated how the pandemic affected endocrine surgery practice. METHODS: PanSurg-PREDICT is an international, multicentre, prospective, observational cohort study of emergency and elective surgical patients in secondary/tertiary care during the pandemic. PREDICT-Endocrine collected endocrine-specific data alongside demographics, COVID-19 and outcome data from 11-3-2020 to 13-9-2020. RESULTS: A total of 380 endocrine surgery patients (19 centres, 12 countries) were analysed (224 thyroidectomies, 116 parathyroidectomies, 40 adrenalectomies). Ninety-seven percent were elective, and 63% needed surgery within 4 weeks. Eight percent were initially deferred but had surgery during the pandemic; less than 1% percent was deferred for more than 6 months. Decision-making was affected by capacity, COVID-19 status or the pandemic in 17%, 5% and 7% of cases. Indication was cancer/worrying lesion in 61% of thyroidectomies and 73% of adrenalectomies and calcium 2.80 mmol/l or greater in 50% of parathyroidectomies. COVID-19 status was unknown at presentation in 92% and remained unknown before surgery in 30%. Two-thirds were asked to self-isolate before surgery. There was one COVID-19-related ICU admission and no mortalities. Consultant-delivered care occurred in a majority (anaesthetist 96%, primary surgeon 76%). Post-operative vocal cord check was reported in only 14% of neck endocrine operations. Both of these observations are likely to reflect modification of practice due to the pandemic. CONCLUSION: The COVID-19 pandemic has affected endocrine surgical decision-making, case mix and personnel delivering care. Significant variation was seen in COVID-19 risk mitigation measures. COVID-19-related complications were uncommon. This analysis demonstrates the safety of endocrine surgery during this pandemic.

Estimation of IZOD impact strength between different concentrations of chitosan-reinforced denture base resins.

BACKGROUND: Poly-methyl methacrylate (PMMA) is an universally acceptable denture base material. Efforts are made to increase the applications with the addition of new constituents. Chitosan has established antifungal properties. The mechanical properties of Chitosan-denture base composite is less evaluated in the literature. This study estimates the differences in impact strength of material for different concentrations of chitosan-reinforced denture base resins. AIM: The study estimated the differences in IZOD impact strength of denture base resin reinforced with 0%, 5%, 10% and 15% of chitosan by weight. MATERIALS AND METHODS: The acrylic samples were fabricated in according to ISO 180 regulations. The study had four test groups (n = 10). ACh0 was the control group with no reinforcements. ACh5, ACh10 and ACh15 had chitosan reinforcement of 5%, 10% and 15% by weight. The samples were processed by conventional heat polymerization cycle and tested in IZOD impact testing machine. The data were recorded and statistically analyzed with Kruskal-Wallis test. RESULTS: The mean impact strength was high in ACh5 (4.25 ± 1.05 kJ/m2) compared to ACh0 (2.88 ± 0.60 kJ/m2), ACh10 (3.63 ± 0.40 kJ/m2), ACh15 (3.38±0.60 KJ/m2). Statistically significant differences between the test groups was determined by Kruskal-Wallis and post hoc Bonferroni test (Chi-square = 12.843, P = .005, df = 3). CONCLUSION: The impact strength of denture base resin increased with 5% chitosan compared with other percentage of chitosan. No statistical significant relationship was observed between the groups.

Effect of zinc oxide nanoparticles on the flexural strength of polymethylmethacrylate denture base resin.

PURPOSE: This study evaluated the flexural strength of polymethyl methacrylate (PMMA) reinforced with various concentrations of zinc oxide (Zn O) nanoparticles. MATERIALS AND METHODS: Nano ZnO was added in 0, 0.4, 0.6, 0.8, 1.2 and 1.4 percentage to PMMA denture base material. 60 specimens of heat cure polymerizing acrylic resin of dimensions 10mm x 4mm x 80mm were fabricated in accordance to ISO 20795-1-2013. The specimens were divided into 6 groups. Acrylic specimens were processed according to manufacturer's instruction. Three-point bending test was performed to evaluate the flexural strength. Surface analysis was performed with scanning electron microscopy (SEM) to observe the fracture surfaces of specimens. ANOVA and Tukey tests were used for the statistical analysis (p < 0.05). RESULTS: Statistical analysis revealed significant differences in strength between groups. The flexural strength improved with the addition ZnO nanoparticles. Highest mean value was observed in Group nZn -14 (91.31 MPa) and lowest in control Group nZn-0 (61.36 MPa). ANOVA and Tukey's honestly significance test found statistical significant differences among the groups ( p<0.001). CONCLUSION: The addition of ZnO nanoparticles in all concentrations increased the flexural strength of acrylic resin when compared to the control group.

Effect of fixed dental prosthesis on the brain functions of partially edentulous patients - pilot study with power spectrum density analysis.

PURPOSE: This study was done to analyse the influence of fixed dental prosthesis (FDP) on brain function by analysing power spectral density of partially edentulous patients. MATERIALS AND METHODS: The study included unilateral missing mandibular molar replacement patients. The patients were restored with three-unit metal ceramic FDP restorations. The cognitive function was analysed with a mental state questionnaire. Power spectral density (PSD) analysis of EEG alpha waves was made pre- treatment, post treatment and 3 months after FDP treatment to analyse the brain function. The data in various phases were obtained before and after chewing. The results were statistically analysed. RESULTS: The mean pre and post treatment PSD was 0.0175 (SD ±0.0132) and 0.0178 (SD ±0.0135). The mean post treatment PSD after three months was 0.024 (SD± 0.019). The results were analysed with repeated ANOVA and were statistically significant. (p<0.01). CONCLUSION: The study displayed improvement in brain function of partially edentulous patients with FDP rehabilitation.